Tropical Cyclone Information Statements

WOCN31 CWHX 071745
Tropical cyclone information statement updated by the Canadian
Hurricane Centre of Environment Canada at 1:48 PM ADT Friday
7 September 2012.
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Tropical cyclone information statement for:
Labrador
Newfoundland
Nova Scotia
Prince Edward Island.
For tropical storm Leslie.
The next statement will be issued by 9:00 AM ADT Saturday.
Leslie weakening just below hurricane strength. Still much
Uncertainty if weather impacts will reach Canada.
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Tropical cyclone information statement ended for:
New Brunswick.
Probability of Leslie's influence in New Brunswick is very low
At this point. However general information statements will
Continue to be issued at WWW.HURRICANES.CA.
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==discussion==
The Canadian Hurricane Centre continues to monitor the evolution of
Leslie. The storm remains parked over the cold water which it has
stirred up. This has resulted in winds dropping below hurricane
force based on hurricane hunter aircraft data this morning.
Leslie should still regain hurricane strength when it eventually
moves, unless it stirs up even cooler water for a longer period.
Most of the computer models still show a slow northward movement with
acceleration early next week. However - as mentioned and now
observed - the computer models are known to have difficulty
simulating these ocean feedback effects and situations where the
atmospheric steering currents are very weak. It is uncertain if
Leslie will even strengthen to category 2 status given the latest
developments - but the storm is quite large with an extensive area of
rainfall, cloud cover and large waves.
In general, the threat of Leslie on Nova Scotia has been decreasing but still enough to bear watching.

The possibility of some impact in
Newfoundland is greater, but still necessarily low (about 30%) for
the Tuesday to Wednesday time-frame next week. This may seem
contradictory to the official track forecast which depicts the storm
center just south of the Avalon Peninsula early Wednesday.
However the position only represents an average of an unusually broad
range. Stay tuned to our updates for the trend in the track and
discussions.
One of The Key weather features that will tell the tale is the
behaviour of a (easier-to-predict) trough of low pressure now
approaching the Great Lakes. This feature is forecast to slowly
intensify and move southeastward over the weekend. During the early
part of next week the computer models are predicting that the trough
will "pick up" the hurricane and drive it northward. There could be
a front merging with the storm and drawing moisture northward along
it. However, all this is contingent on the timing of the trough and
position of the tropical storm/hurricane.
Much smaller but more intense hurricane Michael over 2000 kilometres
east of Leslie now, will also move very slowly and is currently not
expected to affect Eastern Canada. Leslie and Michael will likely
draw closer to each other over the next several days. Since Leslie
is much larger, its possible impact on Michael would likely be to
shear-apart its upper clouds and acellerate it northward away from
Leslie. A true merging of the hurricanes is not expected based on
their differing sizes. But experience with this sort of situation is
limited and we will certainly monitor it.
Moderate surf conditions related to Leslie will persist along
south-facing coastlines of Nova Scotia and Newfoundland throughout
the next several days. If near the water, exercise caution knowing
that wave heights can vary significantly over a span of several
minutes and that rip currents can develop at local beaches.
Incident wave heights near 2 metres (7 feet) may break at the shore
at heights near 3 metres (10 feet).
The Canadian Hurricane Centre will continue issuing these general
information statements today and Saturday with more detailed track
forecasts possibly beginning early Sunday.
Visit WWW.WEATHEROFFICE.GC.CA/HURRICANE/TRACK_E.HTML (all in lower
case) for the latest hurricane track map.
Please also refer to the public and marine forecasts and warnings
issued by Environment Canada for your area.
END/FOGARTY